Urbanization is occurring at an explosive rate, and many cities, especially in low-income countries, are struggling to control growth and stop the development of unplanned communities. This research investigates the in-home environmental health risks associated with planned and unplanned growth in peri-urban communities (neighborhoods) of a rapidly growing city in Northern Mexico. Surveys were conducted during home visits to 98 households in a planned community and 202 households in unplanned communities of comparable, though slightly higher, socio-economic status. To assess the differences for the two types of communities, multiple risk factors were measured and compared. Results showed that households in both planned and unplanned communities were vulnerable to poor environmental health conditions, but more risk factors and negative health outcomes were associated with unplanned communities. Some of the obvious benefits of living in a planned community included better-constructed homes and water and sewer connections. Other study results indicated that households in the planned community reported fewer cases of respiratory problems (P = 0.039) and dizziness (P = 0.009). They were also less likely to store insecticides and other chemicals inappropriately in their home (P < 0.001). Providing adequate housing infrastructure appears to provide a number of important benefits to health and behavior beyond the simple provision of additional amenities in the home.